Adjustable guide for the forming zone of a paper machine

ABSTRACT

A PAPER WEB IS FORMED BETWEEN BETWEEN A PAIR OF CONVERGING FORMING WIRE RUNS. A PLURALITY OF BARS, EACH OF WHICH EXTENDS TRANSVERSELY ACROSS THE WIRE RUNS, FORMS A CONTOURED LONGITUDINALLY EXTENDING GUIDE SURFACE. A THIN GUIDING SHEET, WHICH CONFORMS TO THE CONTOURED GUIDE SURFACE, GUIDES ONE OF THE WIRE RUNS ALONG THE CONTOURED GUIDE SURFACE AND INTO GRADUAL CONVERGENCE WITH THE OTHER WIRE RUN. EACH OF THE PLURALITY OF BARS IS MOUNTED FOR   INDEPENDENT AND SEPARATE ADJUSTMENT TO SELECTIVELY ALTER THE CONTOUR OF THE GUIDE SURFACE.

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A'Fl'ORNI-IYS April 1-971 I D. R. GUSTAFSON 3,574,055

ADJUSTABLE GUIDE FOR THE FORMING ZONE OF A PAPER MACHINE Filed NOV. 15,1967 2 Sheets-Sheet 2 INVIZN'IUR. 04 W0 5 60574550 United States Patent3,574,055 ADJUSTABLE GUIDE FOR THE FORMING ZONE OF A PAPER MACHINE DavidR. Gustafson, Rockton, Ill., assignor to Belort Corporation, Beloit,Wis. Filed Nov. 15, 1967, Ser. No. 683,225 Int. Cl. D21f 1/36 US. Cl.162303 9 Claims ABSTRACT OF THE DISCLOSURE A paper web is formed betweenbetween a pair of converging forming wire runs. A plurality of bars,each of which extends transversely across the wire runs, forms acontoured longitudinally extending guide surface. A thin guiding sheet,which conforms to the contoured guide surface, guides one of the wireruns along the contoured guide surface and into gradual convergence withthe other wire run. Each of the plurality of bars is mounted forindependent and separate adjustment to selectively alter the contour ofthe guide surface.

The instant invention provides for the control of convergence betweenforming wire runs in a web forming zone in a papermaking machine.

In the art of making paper webs from stock streams fed between a pair oftraveling forming wires, there have been various suggestions relative tothe geometry of the socalled forming zone, which is a longitudinalregion or zone extending from a point, approximately at the location ofthe stock stream slice or jet, where the forming wires are fairlyclosely spaced to a point shortly downstream therefrom where the wiresmay be said to have converged, in that they have been brought throughthe process of convergence in order to reach substantial parallelismwith a moist web sandwiched therebetween. In the course of the travel ofthe wire runs through this converging forming zone the stock stream hassome of its downstream velocity component converted to pressure(generally normal to the downstream direction) and drainage of the stockoccurs through one or both of the forming wires in the forming zone bythe driving of water in the pressurized stock through an initial orincipient web being formed on one or both of the forming wires.

The prior art workers have suggested a number of means for effectingconvergence, ranging from rolls of substantial diameter (for presentinga convex curvature to one of the forming wires at the forming zone) todevices in the nature of blades which tend to effect a comparativelyabrupt direction change of the wire being guided thereby in theimmediate vicinity of contact with the blade, although a comparativelystraight line taper from the blade to a converged end of a forming zonemay be effected by this means. The prior art has used such various guidemeans in one way or another; but it has often been found that thesedevices leave something to be desired in the papermaking art.

In the practice of the instant invention, a guiding surface ofcontrolled contour is used to guide one of the opposed forming wiresagainst the other in the forming zone in order to achieve a desiredgradual convergence between the wires. The contoured surface willordinarily impart substantially precisely its contour to the wire runwhich engages the same and it will also impart at least some deflectionto the opposed wire in most paper forming operations by virtue of thefact that the pressure generated within the stock body in the formingzone is ordinarily suflicient to cause some deflection of the opposedwire (or the wire which is free from restraining means in contacttherewith opposite the forming zone). In fact,

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the extent of the deflection of this opposed wire run is determined bythe internal pressure within the stock body in the forming zone.

The idea that there is pressure in the stock body in the forming zone isnot per se new. Instead, skilled workers in the art have recognized thatsuch pressure is desirable in effecting the drainage of the water in thestock through the forming wire or wires, since the water in the stockbody will have a flow through at least a limited amount of felted fibersor incipient web formed on the wire, which incipient web will resist theflow of water to some extent. The instant invention, however, makespossible a rather exacting control of the pressure within the stockbody, so that a number of very useful results may be obtained. As anexample, adjustment of the pressure or pressures throughout the formingzone may be effected by the adjustable guide of the instant invention soas to achieve optimum operating conditions for a given type ofpapermaking stock. On the other hand, in an experimental run it may bedesirable to study a number of different pressures or different pressurechanges in a given stock body in the forming zone, and the instantadjustable guide means is also adapted to function so as to achieve suchinternal stock pressure selectivity.

Other and further objects, features and advantages of the presentinvention will become apparent to those skilled in the art from thefollowing detailed disclosure thereof and the drawings attached heretoand made a part hereof.

On the drawings:

FIG. 1 is a side elevational view with parts broken away and parts shownin section of the converging wire guiding device of the instantinvention; and

FIG. 2 is a sectional view taken substantially along the line 11-11 ofFIG. 1.

As shown on the drawings:

In FIG. 1 there is shown generally a guide housing 10 which carries onthe active face thereof a guiding sheet indicated generally by thereference numeral 11, which sheet 11 defines an elongated convex curvein the longitudinal or machine direction (as shown in section in FIG. 1)for the purpose of guiding a top run 12 of a paper machine forming wiretraveling directly on the face of the sheet 11 for the full length ofthe sheet 11 (such wire 12 being shown essentially only as a line marked12). The wire run 12 is brought into gradual convergence with a lowerwire run also shown as a line 13 in the view of FIG. 1.

The forming wires 12 and 13 are conventional forming wires which aremounted under tension (by means which are conventional but which are notshown) for travel at substantially the same speed and also atsubstantially the speed of a stock jet stream indicated partially at Jat the upstream end of the forming zone which is indicated generally bythe reference letters FZ at the bottom of FIG. 1. At the off-runningside of the forming zone FZ, it will be appreciated that the wires 12and 13 travel in substantial parallelism with a moist web sandwichedtherebetween and designated in the schematic view of FIG. 1 with thereference letter W.

At the upstream end of the forming zone FZ, it will be appreciated thatthe wires 12 and 13 are spaced apart by a distance here designated H,which is ordinarily a very small dimension in the neighborhood ofperhaps 0.2 inch up to /2 inch or in some instances as much as 1 inch oreven 1 /2 inches. The dimension H represents essentially the spacingfrom the wire 12 on the contoured surface of the sheet 11 to a D-lineabscissa here indicated D,,, which is substantially longitudinallyaligned with the other wire 13, as here shown, although it is primarilya straight line which functions as an abscissa for the ordinate line Hhere indicated. Using the ordinate line H and an abscissa D,, as aconventional reference, it will be appreciated that the spacing of thewire 12 from the abscissa D will be the variable H, which varies inaccordance with the downstream dimension from the ordinate H which ishere designated merely D. H and D are both dimensions in inches in thedrainage curve: H =CD wherein H is the distance in inches from the wire12 (or the surface of the sheet 11) to the abscissa line or D-line whichis substantially longitudinally aligned (i.e. substantially in thedirection of the wire 13); D is the distance in inches downstream fromthe large end of the converging forming zone (e.g. about at theintersection of H and D,,); C is a constant varying from 0.1 to 1.6; andk is a constant varying from 0.2 to 2 in the extremes, but preferablyhere within the range of 1 to 2. A more complete discussion of thedrainage curve and the various operative parameters will be found in E.I. Justis US. Pat. No. 3,383,143.

The curve thus defined by the formula H=CD is an elongated convexnon-circular curve wherein the radius tends to increase as the curveextends downstream through the forming zone FZ. Essentially, this curveis the drainage curve for papermaking stock. It will be appreciated,however, that the particular drainage curve for any given type of stockwill involve a certain amount of selectivity relative to the constants Cand k. Ideally, the selection of C and k in the definition of aparticular curve for the contour of the guiding surface of the sheet 11would result in a forming zone wherein the internal pressure remainssubstantially constant during the drainage of the stock throughout theforming zone. It will be appreciated, however, that drainage curves arenot necessarily available for each and every type of stock and mayrequire a considerable amount of experimentation in certain instances.As a consequence, the instant invention affords the advantage ofcontrolling the precise contour of the sheet 11 so that an operator mayarrive at a contour for the sheet 11 which does conform substantiallywith the ideal drainage curve and/or does achieve ideal conditions inthe forming zone during operation of the machine.

The sheet 11 is formed of preferably comparatively thin non-corrosivematerial such as 0.030 inch thick stainless steel, having a transversedimension T that is substantially that of the forming wire runs, asindicated in FIG. 2. In the embodiment of FIG. 1, the longitudinaldimension of the sheet 11 is a total of about 25 inches, but theinitially folded portion 11a and the initially curved portion 11bconstitute approximately inches so that the overall dimension remainingis only about 20 or 21 inches for the controlled contour sheet portionHe that is actually employed in the forming zone FZ.

With reference to the overall housing 10, it will be seen that the samecomprises a top 21, a front wall 22 and a side wall 23 which has anopposite or mating back side wall 24 indicated in FIG. 2. The front wall22 carries a curved solid shoe portion 22a about which the sheet portion11b is wrapped and the shoe 22a is carried on a plate 22b secured to thefront bottom of the front wall 22 in conventional manner. The side walls23 and 24 have outwardly extending support flanges 23a and 24a weldedthereto, and windows at 23b, 23c and at 24c as indicated in FIG. 2. Itwill be appreciated that there is another window 24b (not shown) on theback side 24 and the window in the position 23c is removed with certainparts broken away in the view of FIG. 1. Such elements 23b, 23c, 240,etc. can be windows or merely bolted plates that are readily removablefor purposes of selective adjustment of the elements therein which willbe described in detail hereinafter. To complete the housing there is arear transverse housing element indicated generally at 25 in FIG. 1which is indicated as mounting for limited longitudinal adjustment arear plate 25a (via an adjustable lock nut arrangement 25b) and carriedon a flange 25c.

It will also be noted that the entire housing 10 carrying the sheet 11in predetermined contour is swingably 4 mounted about a rear pivot 26(having an opposite rear counterpart not shown) which pivot 26 is heldin position by the remainder of the framing shown partially only at 27,but in an essentially conventional pivot arrangement mounted for limitedvertical adjustment.

Likewise, in an essentially conventional pivot arrangement employingother vertically movable structure indicated partially at 28 and 28a,and carrying a fixed pivot 29, 29a, it will be seen that the forward endof the overall housing 10 is swingably mounted about a pivot linethrough the pivots 29-29a swingably mounting the top front of thehousing 10 via upright ears 30, 30a reinforced by plates 31, 31a allsecured to the side walls 23 and 24 by welding or other conventionalmeans.

Essentially the pivots 26 and 29 are conventional, but in the instantdevice it will be appreciated that in each case the pivots 36 and 39 areremote from the sheet 11 but afford swinging movement thereof relativeto the wire runs 12 and 13. This type of adjustment is afforded readilyby using piston-cylinder means, jack-screws, or any number of otherconventional means (not shown).

Essentially, the contour of the active portion 110 of the thin sheet 11is controlled by a longitudinal succession of transverse bars designated40, 50, 60, through 130, which bars 40, etc. are substantially rigid andunyielding relative to the thin sheet 11 and may be constructed ofhollow or solid cross section but extend transversely substantially thetransverse dimension T of the thin sheet 11 and the wires 12 and 13. Thetransverse bars 40, 50, etc. are shown in full view in FIG. 1 as havinggenerally rounded bottoms (e.g. designated at 70a, a, a, etc.) so thatthey will engage the back side of the sheet 11 along relatively uniformbut comparatively thin (longitudinally) surfaces or edges, although forthe full width of the back side of the sheet 11, as indicated in FIG. 2for the rounded surface 50a for the bar 50. The bars 40, 50, 60, etc.are also shown herein as being freely slidable relative to each otheralong the contiguous faces thereof. Thus the bars 40, 50, 60, etc aremounted in longitudinal succession (actually with contiguous facesslidably engaging each other) between a spacer 220 on the forward plate22b and the rear plate 25a. Movement of each of the bars 40, 50, 60 isthus limited essentially to movement of each generally in a transverselyaligned plane which is only approximately normal or perpendicular to theback side of the sheet 11 but is generally perpendicular to thelongitudinal or machine direction and such planes are longitudinallyspaced for the relative movement of the longitudinal succession of bars40, 50, 60, etc.

Referring specifically to the mounting for the transverse bar 50 shownin FIG. 2, it will be seen that the front and back side walls 23, 24mount bearing sleeves 23 24 respectively, which receive stub shafts 51a,51b, respectively, extending from the ends of a main enlarged supportshaft 51. The main cross support shaft 51 functions as a pivot for therod assemblies 52 and 152 swingably mounted and carried thereby. The rodassembly 52 is composed of a top apertured element 53 which has theround bearing aperture 53a that permits the same to be slidably receivedfor swinging movement on the cross shaft 51. The bottom of the rodassembly 5 2 is provided with a conventional pivot connection 54 definedby an upstanding apertured ear 54a secured to the top of the bar 50adjacent the front side wall 23, and an apertured bifurcated member 5412(with the pivot pin 54c interconnecting the same) extending up from thepivot connection 54 to a turn-buckle-like arrangement for con nectingthe top portion 53 with the bottom portion 54b of the rod assembly. Theturn-buckle-like element 55 is formed of a central enlarged section 55awith threaded rod connections 55b and 55a extending into threadedrecesses in the top 53 and bottom 54b elements previously described andlocked temporarily in position therein by the lock nuts 55d and 55a,respectively. It will be appreciated that any conventionalturn-buckle-type or other axially expansible or contractible element maybe used in the rod assembly 52 in order to effect (by the threadedconnections or otherwise) limited expansion or contraction of the rodassembly 52 so as to effect limited movement of the end of the bar 50connected to such rod assembly 52 (toward or away from the thin sheet11). This type of adjustable rod connection 52 is substantiallyduplicated at the opposite end of the bar 50, adjacent the rear wall 24by the assembly 152., wherein other elements corresponding to thosealready described are given the same reference numeral in the 100series. By the use of the two adjustable rod assemblies 52 and 152, itwill be appreciated that limited adjustment of the position of the bar50 is afforded relative to the action applied by the bar 50 against thethin sheet 11. The separately and independently adjustable rodassemblies 52 and 152 afford what would appear in FIG. 2 to be a tiltingtype of adjustment of the bar 50 (which tilting type of adjustment isnecessarily limited to that allowable by the pivotal type connectionsactually employed here), although such tilting type of adjustment (tothe extent that it would be needed) is available.

It will also be appreciated that once the rod assemblies 52 and 152 areadjusted to the extent desired by the primary type of adjustment that isafforded by these rod assemblies 52 and 152, the assemblies will bebacked against the main cross-rod support 51, and the relative elevationof the cross-rod 51 will fix the relative elevation of the active bottomface or edge 50a of the cross bar 50 acting against the sheet 11 andactually defining its contour. In FIG. 2, it would appear that the stubshafts 51a and 51b which are received in the bearing sleeves '23 and24], respectively, are aligned on the axis of the round cross-rod 51,but it is apparent from FIG. 1 that this is not the case. Instead, thestub shafts 51a and 51b have eccentric or off-center mountings, asindicated from the side view of FIG. 1 so that by application of arotating force to the nut head extremity 51c indicated in FIG. 1, aslight eccentric rotation of the main support cross-rod 51 is possibleand this in turn will cause a very slight change in the elevation of thebar 50 relative to the thin sheet 11, and thus an adjustment of theactive face of the thin sheet 11 in the immediate vicinity of the activeface 50a for the bar 50. This is a very fine adjustment via theeccentric stub shaft 51a and it affords a controlled and simultaneousmovement of the entire bar 50 so that it will act against the entiretransverse dimension of the thin sheet 1 1 which engages the active faceor edge 50a for the cross bar 50.

It will be appreciated that the ramaining bars 60, 70, 80, etc. are allshiftable in their respective generally vertical planes in substantiallythe manner hereinbefore described relative to the cross bar 50. By suchselective, separate and independent adjusting means for each of thesebars 40, 50, etc. it is possible to effect predetermined and selectivechanges in the contour of the active portion of the sheet 110 which willin turn guide the wire runs 12 and 13 through a different butpredetermined and selected contour of convergence.

It will also be appreciated that the sheet active portion 110 can onlybe anchored at the upstream end 11a or 11b, if it is to carry out thefunction herein required, because the relative shifting of the bars 40,50, 60, etc. may effect a sufficient change in the contour of the sheetportion 110 as to require some very slight longitudinal shifting at thedownstream extremity thereof. On the other hand, the spacing between theactive faces for the bars, e.g., 70a to 80a to 90a, etc. is so smallthat the structural strength of the thin sheet 110 is sufficient tobridge between these supporting surfaces and to resist pressure exertedagainst the sheet by stock within the forming zone FZ acting against thewire 12. Thus, the general contour of the travel of the wire 12 will bein substantial conformance with the relatively smooth curve that will bedefined by the active sheet portion 11c as it bridges from one activeface to the next of the longitudinal succession of bars 40, 50, etc. Thesheet portion 11c will change its contour in response to the relativeshifting of the bars 40, 50, 60, but it yields to contour changes inresponse to these superior forces, whereas the sheet has sufficientstrength to resist the comparatively smaller forces generated within thebody of the stock in the forming zone FZ so that the thin sheet portion110 will, in fact, control the contour of the wire 12,.

The support and adjustable control mountings for each of the bars 60,70, 80, etc. are indicated with the same reference numerals but in the60, 70, 80, etc. series respectively. This means (e.g. the bars 40, 50,etc.) are carried in the housing 10 for controlling the contour of thesheet 11 and thus the wires 12 and 13; and such control means areswingably mounted via the housing for movement to control the locationof such contour of the sheet 11 vis-a-vis the wires 12 and 13. Theadjustments available herein thus include physical displacement of thecontoured sheet .11 (as a whole, via the pivot adjustments which actseparately and independently of the contour adjusting bars 40, 50, etc.)and the separate and independent contour adjusting means 40, 50, etc.

It will be understood that modifications and variations may be effectedwithout departing from the spirit and scope of the novel concepts of thepresent invention.

I claim as my invention:

1. In a paper forming machine wherein a paper web is formed betweenconverging forming wire runs, a device for guiding a traveling porouswire comprising, a thin guiding sheet of substatnially the wiretransverse dimension positioned to present to the wire a contouredlongitudinally extending guide surface for engaging and guiding thetravel of such wire in accordance with such contour, a plurality oftransversely extending bars in longitudinal succession engaging thesurface of said sheet opposite its guide surface, and separate andindependent adjustable means connected to each of said bars forselectively urging each of said bars against said sheet to selectivelyalter the contour of such sheet guide surface.

2. The device of claim 1 wherein said adjustable means for each barcomprises transversely spaced means acting together to move oppositeends of such bar equally toward and away from said sheet.

3. The device of claim 1 wherein said adjustable means for each barcomprises a transversely spaced pair of rods each connected to one endof the bar and a transverse backing support, each of said rods beingaxially expansible for acting against said backing support toindependently move the end of the bar connected thereto, and each suchbacking support being movable to act simultaenously on both ends of abar via the rods connecting the same therewith.

4. In a paper making machine forming zone, in combination, a pair ofopposed tensioned forming wire runs traveling longitudinally fromclosely spaced relationship in such forming zone gradually through andto convergence, a thin guiding sheet of substantially transversedimension of such wire runs positioned to present to one such run alongitudinally convexly contoured guide surface causing such convergencebetween the wire runs at such forming zones, and adjustable meanspositioned to present to the sheet side opposite such contoured surfacea plurality of rigid members, each of said plurality of rigid membersbeing mounted for separate and independent adjustment in longitudinallyspaced generally transversely aligned planes for deforming the sheet tocontrol such contour.

5. The machine of claim 4 wherein such adjustable means comprised aplurality of transversely extending bars positioned to present to suchsheet opposite its guide surface a plurality of longitudinally spacededges in control of the guiding contour of such sheet, primary adjustingmeans acting directly on each such bar for selectively actuating suchbar to control such sheet contour, and secondary adjusting means actingon each such bar through connection with said primary means.

6. The machine of claim 5 wherein said sheet and said adjustable meansare carried in a housing swingable about a point remote from said sheetfor limited adjustment of the sheet as a whole relative to the wireruns.

7. The machine of claim 4 wherein said sheet and said adjustable meansare carried on a housing swingable about a point remote from said sheetfor limited adjutment of the sheet as a whole relative to the wire runs.

8. In a paper forming machine as defined in claim 1 wherein eachadjustable means comprises a plurality of transversely extending barspositioned to present to such sheet opposite its guide surface aplurality of longitudinally spaced edges in control of the guidingcontour of such sheet, primary adjusting means acting directly on eachsuch bar for selectively actuating such bar to control such sheetcontour, and secondary adjusting means References Cited UNITED STATESPATENTS 3,382,143 5/1968 Justus et a1 162- 303 s. LEON BASHORE, PrimaryExaminer A. DANDREA, I 11., Assistant Examiner U.S. Cl. X.R. 162203UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3574,055 Dated Apr l1 6, 1971 Inventor(s) D. R. Gustafson It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 2, line 9, "a" (first occurrence thereof) should re; to-.

Column 3, lines 15-18, delete the sentence "a more comple 3, 383, 143.".

Column 4, line 17, "36 and 39" should read--26 and 29--.

Column 5, line 37, "of" should read--in--;

line 49, "ramaining" should read-remalning--. Column 6, line 32,"substatnlally" should. read-substantiall Column 7, line 9, "'adjutment"should read-adjustment".

Signed and sealed this 19th day of October 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSGHALK Atteating Officer ActingCommissioner of Patent 1 FORM PO-1050 (10-69) uscoMM-oc so:

